Use the meson summary instead of manually building our summary with message

Ran ninja reconfigure and verified the output.

purple-plugin-pack 2.8.1dev

  libpurple
    install directory: /usr/local/lib/purple-2
    data directory   : /usr/local/share
    plugins          : autoreply, bash, capsnot, colorize, dewysiwygification, dice, eight_ball, flip,
                       google, groupmsg, highlight, ignore, irc-more, irchelper, listhandler, ning,
                       oldlogger, omegle, showoffline, simfix, slashexec, snpp, splitter, sslinfo,
                       translate, xmppprio

  pidgin
    install directory: /usr/local/lib/pidgin
    data directory   : /usr/local/share
    plugins          : album, blistops, convbadger, difftopic, enhancedhist, gRIM, icon-override, irssi,
                       lastseen, listlog, mystatusbox, nicksaid, plonkers, schedule, sepandtab,
                       switchspell, timelog

  finch
    install directory: /usr/local/lib
    data directory   : /usr/local/share
    plugins          :

  User defined options
    backend          : ninja